This allows for accurate measurement of time while introducing leap seconds to ensure that the time does not deviate from UT1 by more than 0.9 seconds. UTC uses the measurement of a second as defined by TAI. That led to the development of Coordinated Universal Time ( UTC), which brought together the best of the both units. This means that we will eventually have our clock noon deviate substantially from the solar noon. This precision is both a blessing and a curse as TAI is so exact that it deviates from UT1 (or what we call civil time). Using atomic clocks in multiple laboratories across the earth, we get the most accurate and constant measure of the second, which allows us to compute time intervals with the highest accuracy. TAIĪs a result, the International Atomic Time ( TAI) was designed to be as precise as possible. GPS triangulation is a good example of a time-sensitive process, in which being a second off results in a completely different location on the globe. Although this is not a problem for most applications, it becomes a non-trivial problem when we require really precise measurements. Even if this seems precise enough, it still has issues due to the gravitational pull of the moon, tides, and earthquakes, the days change length all year long. Today, we use stars and quasars to measure how long it takes for the Earth to perform a full rotation around the sun. This gave birth to Universal Time ( UT1), the successor of GMT (Greenwich Mean Time). One of the simplest ways to measure a second is as a fraction of the day, given that we can reliably guarantee the sun will rise and set every day (in most places). We can then use other time references-such as days, weeks, or years-using a calendar standard as multiples of the second (see Gregorian Calendar as an example). The same way we have standards to measure weight or length that define kilograms or meters, we need an accurate way to define what a ‘ second’ means. The first concept to grasp when working with time is a standard that defines how we can measure units of time. Otherwise, given the complexity of date- and time-related issues, introducing unexpected bugs is easy. datetime is one of those APIs that seems easy to use, but requires the developer to have a deep understanding of what a few things actually mean. There are few other ways to find the uptime and output header of command “w” is similar to that of output of “uptime” command.When trying to make things work with the datetime module, most Python users have faced a point when we resort to guess-and-check until the errors go away. Version information can be shown using option ~]$uptime -V Option “s” is used to get the starting time/specified time when the system started has been ~]$uptime -s Just to make sure you get the uptime in human-readable format, you can use option ~]$uptime -p V, -version output version information and exit This will give the options available to the preceding ~]$uptime -h Uptime has got few options to tailor outputs and to those who are unaware of the options of the newbies working with uptime can use the option “-h” (which means help). SORT command in Linux/Unix with examplesĠ8:24:37 up 207 days, 11:10, 0 users, load average: 0.00, 0.03, 0.05įrom the above code, the output has got four parts: Current time, Uptime, Number of Users, and average load as mentioned earlier.AWK command in Unix/Linux with examples.Sed Command in Linux/Unix with examples.How to Change Root Password in Kali Linux?.How to Change the username or userID in Kali Linux?.
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